LONDON (AFP) - Britain's new FBI-style crime-fighting agency was launched on Monday with a threat to hit the country's most "horrible" criminals with a robust response.

The National Crime Agency (NCA) has 4,500 dedicated officers and is aimed at tackling the estimated 37,000 criminals involved in serious and organised crime blighting Britain.

"There will be no one beyond the reach of law enforcement or beyond the reach of the NCA," said its director general Keith Bristow.

"Those people involved in the most horrible activities can expect the most comprehensive and robust response." The agency has an annual budget of £500 million (S$623 million) and focuses on five key areas: organised crime, economic crime, border policing, child exploitation and online protection, and cyber crime.

Although focusing on crime in Britain, it will place around 120 officers in 40 different countries.

Unlike the US Federal Bureau of Investigation, it does not have responsibility for counter-terrorism, which is dealt with by police. A review will examine whether such operations should move to the NCA in future.

It is the third attempt in 15 years to set up a "British FBI", a move which has been met by scepticism from critics.

The NCA replaces the Serious Organised Crime Agency (Soca), itself established in 2006 to succeed the National Crime Squad set up in 1998.

The opposition Labour party said the new agency was simply a rebranding exercise designed to disguise policing cuts.

"Most of the NCA is just the rebranding of existing organisations such as SOCA, but with a substantial 20 per cent cut imposed by the Home Office in their overall budget," said Labour's policing spokesman David Hanson.

"The new organisation is not strong enough to deal with the exponential growth of economic and online crime."

The agency undertook its first major operation on Monday in a crackdown on suspected identity fraudsters.

Five people were arrested following raids in London, Liverpool and three towns in England and Scotland.

The arrested individuals were suspected of fraudulently applying for genuine passports or driving licences using hijacked or stolen identities.